阅读说明：本技术 一种铝或铝合金表面微弧氧化膜层的制备方法 (Preparation method of micro-arc oxidation film layer on surface of aluminum or aluminum alloy ) 是由 王晓波 全风美 法涛 史鹏 杨国华 朱生发 于 2019-10-24 设计创作，主要内容包括：本发明涉及微弧氧化膜层的制备技术领域,尤其涉及一种铝或铝合金表面微弧氧化膜层的制备方法。本发明提供的铝或铝合金表面微弧氧化膜层的制备方法,包括以下步骤：提供微弧氧化处理液；将铝或铝合金在所述微弧氧化处理液中进行微弧氧化处理；所述微弧氧化处理的温度≥90℃。本发明所述的微弧氧化处理温度一方面可以提高成膜速度,另一方面可以提高膜层的外层疏松层的溶解速率,保证成膜速率和外层疏松层的溶解速率保持在一个较为匹配的状态,以利于提高膜层质量；同时,由于本发明所述的微弧氧化处理温度在90℃以上,避免了低温微弧氧化处理带来的成本高和易造成资源浪费的问题。(The invention relates to the technical field of preparation of micro-arc oxidation film layers, in particular to a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy. The invention provides a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy, which comprises the following steps: providing micro-arc oxidation treatment liquid; carrying out micro-arc oxidation treatment on aluminum or aluminum alloy in the micro-arc oxidation treatment liquid; the temperature of the micro-arc oxidation treatment is more than or equal to 90 ℃. The micro-arc oxidation treatment temperature can improve the film forming speed on one hand and improve the dissolution rate of the outer loose layer of the film layer on the other hand, so that the film forming speed and the dissolution rate of the outer loose layer are kept in a relatively matched state, and the quality of the film layer is improved; meanwhile, the micro-arc oxidation treatment temperature is over 90 ℃, so that the problems of high cost and easy resource waste caused by low-temperature micro-arc oxidation treatment are solved.)

1. The preparation method of the micro-arc oxidation film layer on the surface of the aluminum or the aluminum alloy is characterized by comprising the following steps of:

providing micro-arc oxidation treatment liquid;

carrying out micro-arc oxidation treatment on aluminum or aluminum alloy in the micro-arc oxidation treatment liquid;

the temperature of the micro-arc oxidation treatment is more than or equal to 90 ℃.

2. The preparation method of claim 1, wherein the micro-arc oxidation treatment is carried out by using a device comprising a direct current pulse micro-arc oxidation power supply, an electrolytic bath, a stirring system and a heating system.

3. The method of claim 2, wherein the electrolytic cell comprises a stainless steel cell body and a reflow hood.

4. The method according to claim 1, wherein the micro-arc oxidation treatment has a pulse frequency of 50 to 2000Hz and a pulse width modulation range of 50 to 5000. mu.s.

5. The method according to claim 1, wherein the current density during the micro-arc oxidation treatment is 2 to 30A/dm²And the micro-arc oxidation treatment time is 15-25 min.

6. The preparation method according to claim 1, wherein the micro-arc oxidation treatment fluid comprises a main film forming agent, a pH regulator and a solvent.

7. The method of claim 6, wherein the main film former is sodium silicate and/or potassium silicate;

the concentration of the main film forming agent in the micro-arc oxidation treatment liquid is 10-150 g/L.

8. The method according to claim 6, wherein the pH adjuster is sodium hydroxide and/or potassium hydroxide;

the concentration of the pH regulator in the micro-arc oxidation treatment liquid is 0.5-3 g/L.

9. The preparation method according to claim 1 or 6, wherein the micro-arc oxidation treatment liquid further comprises a film structure modifier;

the film structure regulator is one or more of NaF, sodium tungstate, EDTA disodium, sodium molybdate, sodium hexametaphosphate, sodium borate and trisodium phosphate;

the concentration of the film structure regulator in the micro-arc oxidation treatment liquid is 0-30 g/L.

10. The method according to claim 1, wherein the micro-arc oxidation treatment liquid is preheated to a temperature for micro-arc oxidation treatment before the micro-arc oxidation treatment.

Technical Field

The invention relates to the technical field of preparation of micro-arc oxidation film layers, in particular to a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy.

Background

Pure aluminum or aluminum alloys have characteristics of small density, high specific strength, easy formability, etc., and thus are used in almost all industrial sectors. However, pure aluminum and aluminum alloy have the defects of poor wear resistance and corrosion resistance, low heat resistance, small rigidity and the like, so that the application of pure aluminum or aluminum alloy is greatly limited.

The micro-arc oxidation, also called plasma micro-arc oxidation, is a method for generating a ceramic film layer by putting metals such as magnesium, aluminum, titanium and the like and alloys thereof into an electrolyte solution and generating spark discharge on the surfaces of the metals such as magnesium, aluminum, titanium and the like and the alloys thereof under the combined action of high temperature, high pressure, thermochemistry, plasma chemistry, electrochemistry and the like. The method has the characteristics of simple process, less environmental pollution, high efficiency and the like, and the ceramic film layer obtained by micro-arc oxidation has the advantages of strong film-substrate binding force, wear resistance, corrosion resistance, high-temperature oxidation resistance, good insulativity and the like. Therefore, the micro-arc oxidation film prepared on the surface of pure aluminum or aluminum alloy by micro-arc oxidation has good prospect.

Because the temperature is one of the factors influencing the micro-arc oxidation discharge characteristic, the film growth and the film quality, at present, the temperature for preparing the micro-arc oxidation film on the surface of the alloy is mainly below 60 ℃. However, studies have shown that the film quality decreases with increasing temperature in the range below 60 ℃. Therefore, in order to ensure the quality of the film layer, the temperature of the electrolyte needs to be maintained below 40 ℃. And a large amount of heat can be generated in the micro-arc oxidation treatment process to continuously raise the temperature of the electrolyte, so that the temperature of the electrolyte is not controlled. Thus, in order to ensure that the temperature of the electrolyte can be maintained below 40 ℃, additional cooling equipment is needed, and the investment and the generated heat of the cooling equipment are taken away, so that the production cost and the waste of resources are greatly increased.

Disclosure of Invention

The invention aims to provide a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy, which can ensure the quality of the prepared micro-arc oxidation film layer at the temperature of more than 90 ℃.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy, which comprises the following steps:

providing micro-arc oxidation treatment liquid;

carrying out micro-arc oxidation treatment on aluminum or aluminum alloy in the micro-arc oxidation treatment liquid;

the temperature of the micro-arc oxidation treatment is more than or equal to 90 ℃.

Preferably, the device adopted by the micro-arc oxidation treatment comprises a direct current pulse micro-arc oxidation power supply, an electrolytic bath, a stirring system and a heating system.

Preferably, the electrolytic bath comprises a stainless steel bath body and a reflux hood.

Preferably, the pulse frequency of the micro-arc oxidation treatment is 50-2000 Hz, and the pulse width regulation range is 50-5000 mus.

Preferably, the current density in the micro-arc oxidation treatment process is 2-30A/dm²And the micro-arc oxidation treatment time is 15-25 min.

Preferably, the micro-arc oxidation treatment fluid comprises a main film forming agent, a pH regulator and a solvent.

Preferably, the main film forming agent is sodium silicate and/or potassium silicate;

the concentration of the main film forming agent in the micro-arc oxidation treatment liquid is 10-150 g/L.

Preferably, the pH regulator is sodium hydroxide and/or potassium hydroxide;

the concentration of the pH regulator in the micro-arc oxidation treatment liquid is 0.5-3 g/L.

Preferably, the micro-arc oxidation treatment liquid also comprises a film structure regulator;

the film structure regulator is one or more of NaF, sodium tungstate, EDTA disodium, sodium molybdate, sodium hexametaphosphate, sodium borate and trisodium phosphate;

the concentration of the film structure regulator in the micro-arc oxidation treatment liquid is 0-30 g/L.

Preferably, before the micro-arc oxidation treatment, the micro-arc oxidation treatment liquid is preheated to the temperature of the micro-arc oxidation treatment.

The invention provides a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy, which comprises the following steps: providing micro-arc oxidation treatment liquid; carrying out micro-arc oxidation treatment on aluminum or aluminum alloy in the micro-arc oxidation treatment liquid; the temperature of the micro-arc oxidation treatment is more than or equal to 90 ℃. The micro-arc oxidation treatment temperature can improve the film forming speed on one hand and improve the dissolution rate of the outer loose layer of the film layer on the other hand, so that the film forming speed and the dissolution rate of the outer loose layer are kept in a relatively matched state, and the quality of the film layer is improved;

meanwhile, the micro-arc oxidation treatment temperature is over 90 ℃, so that the problems of high cost and easy resource waste caused by low-temperature micro-arc oxidation treatment are solved.

Drawings

FIG. 1 is a diagram of the apparatus used for the micro-arc oxidation treatment, wherein 1-a heating control system, 2-a stirring control system, 3-a heating rod, 4-a stirrer, 5-aluminum or aluminum alloy, 6-an anode rod, 7-electrolyte, 8-a stainless steel tank, 9-a cathode and anode insulating sleeve, and 10-a reflux hood.

Detailed Description

The invention provides a preparation method of a micro-arc oxidation film layer on the surface of aluminum or aluminum alloy, which comprises the following steps:

providing micro-arc oxidation treatment liquid;

carrying out micro-arc oxidation treatment on aluminum or aluminum alloy in the micro-arc oxidation treatment liquid;

the temperature of the micro-arc oxidation treatment is more than or equal to 90 ℃.

In the present invention, all the raw materials used in the treatment are commercially available products well known to those skilled in the art, unless otherwise specified.

The invention provides a micro-arc oxidation treatment fluid; the micro-arc oxidation treatment liquid comprises a main film forming agent, a pH regulator and a solvent. In the invention, the main film-forming agent is preferably sodium silicate and/or potassium silicate, and when the main film-forming agent is sodium silicate and potassium silicate, the proportion of the sodium silicate and the potassium silicate is not limited in any way, and the main film-forming agent and the potassium silicate can be mixed according to any proportion. In the present invention, the pH adjuster is preferably sodium hydroxide and/or potassium hydroxide; when the pH regulator is sodium hydroxide and potassium hydroxide, the proportion of the sodium hydroxide and the potassium hydroxide is not limited in any way, and the sodium hydroxide and the potassium hydroxide are mixed according to any proportion. In the present invention, the solvent is preferably distilled water.

In the invention, the concentration of the main film forming agent in the micro-arc oxidation treatment liquid is preferably (10-150) g/L, more preferably (105-150) g/L, and most preferably (110-140) g/L; the concentration of the pH regulator in the micro-arc oxidation treatment liquid is preferably (0.5-3) g/L, more preferably (0.8-2.5) g/L, and most preferably (1.5-2.0) g/L.

In the invention, the micro-arc oxidation treatment solution preferably further comprises a film structure regulator; the membrane layer structure regulator is preferably one or more of NaF, sodium tungstate, EDTA disodium, sodium molybdate, sodium hexametaphosphate, sodium borate and trisodium phosphate; when the film structure regulator is more than two of the specific choices, the specific proportion of the specific substances is not limited by any special limit, and the specific substances are mixed according to any proportion; in the invention, the concentration of the film structure regulator in the micro-arc oxidation treatment liquid is preferably (0-30) g/L.

In the present invention, the method for preparing the micro-arc oxidation treatment solution preferably includes the steps of:

and mixing the main film forming agent, the pH regulator, the film structure regulator and the solvent to obtain the micro-arc oxidation treatment fluid.

In the present invention, the mixing is preferably performed under stirring, and the stirring is not particularly limited in the present invention, and the solution may be uniformly mixed by stirring using a stirring process known to those skilled in the art.

In the invention, the main film-forming agent, the pH regulator, the membrane layer compactness regulator and the solvent are preferably mixed by adding the main film-forming agent, the pH regulator and the membrane layer compactness regulator into the solvent; the main film forming agent, the pH regulator and the film layer compactness regulator are added into the solvent in any sequence without any special limitation, and the main film forming agent, the pH regulator and the film layer compactness regulator are mixed in any sequence.

The composition of the aluminum alloy is not particularly limited in the present invention, and an aluminum alloy known to those skilled in the art may be selected.

In the invention, the aluminum or the aluminum alloy is preferably pretreated before the micro-arc oxidation treatment; the pretreatment is preferably oil removal cleaning; the degreasing cleaning is not limited in any way, and the aluminum or aluminum alloy can be cleaned by adopting a degreasing cleaning process well known to those skilled in the art.

In the invention, the equipment used for micro-arc oxidation treatment preferably comprises a direct current pulse micro-arc oxidation power supply, an electrolytic bath, a stirring system and a heating system; in the invention, the anode of the direct current pulse micro-arc oxidation power supply is preferably connected with an anode rod through a lead, and the cathode of the direct current pulse micro-arc oxidation power supply is linked with a stainless steel electrolytic tank; in the present invention, the electrolytic bath preferably comprises a stainless steel bath body and a reflux hood; the stainless steel tank body and the reflux cover preferably form a closed electrolysis system; the electrolytic cell is preferably provided with a cathode-anode insulating sleeve above the side wall of the electrolytic cell, the cathode-anode insulating sleeve is preferably used for placing the anode rod, and the anode rod is preferably connected with aluminum or aluminum alloy through a lead; the aluminum or aluminum alloy is preferably placed in the electrolyte inside the stainless steel tank body; in the present invention, the heating system preferably comprises a heating control system and a heating rod; the heating rod is preferably placed in the electrolyte, and the material of the heating rod is preferably stainless steel; the agitation system preferably includes an agitation control system and an agitator, which is preferably disposed within the electrolyte (as shown in fig. 1). FIG. 1 is a diagram of the apparatus used for the micro-arc oxidation treatment, wherein 1-a heating control system, 2-a stirring control system, 3-a heating rod, 4-a stirrer, 5-aluminum or aluminum alloy, 6-an anode rod, 7-electrolyte, 8-a stainless steel tank, 9-a cathode and anode insulating sleeve, and 10-a reflux hood.

In the invention, before the micro-arc oxidation treatment, the micro-arc oxidation treatment solution is preferably preheated to the micro-arc oxidation treatment temperature, and then the aluminum or aluminum alloy is firmly connected by an aluminum electrode or an aluminum wire and then placed in an electrolytic bath containing the micro-arc oxidation treatment solution so as to carry out the subsequent micro-arc oxidation treatment.

In the invention, the temperature of the micro-arc oxidation treatment is more than 90 ℃; in the present invention, the upper limit of the temperature of the micro-arc oxidation treatment is preferably a temperature at which the solution is kept boiling. In the invention, the pulse frequency of the micro-arc oxidation treatment is preferably 50-2000 Hz, more preferably 50-480 Hz, and most preferably 100-400 Hz; the pulse width adjustment range is preferably 50-5000 μ s, more preferably 500-4500 μ s, and most preferably 1500-3500 μ s.

In the invention, the current density in the micro-arc oxidation treatment process is preferably 2-30A/dm²More preferably 21 to 30A/dm²Most preferably 24 to 28A/dm²(ii) a The time for the micro-arc oxidation treatment is preferably 15-25 min, and more preferably 20 min.

After the micro-arc oxidation treatment is finished, the post-treatment is preferably carried out; the post-treatment is washing and drying which are sequentially carried out; the washing is preferably water washing, and the drying is preferably natural air drying or oven drying.

In the invention, the thickness of the micro-arc oxidation film layer prepared by the preparation method is preferably 20-30 μm, and the surface roughness is preferably 1.5-2.0.

The following will explain the preparation method of the micro-arc oxidation film layer on the surface of aluminum or aluminum alloy in detail with reference to the examples, but they should not be construed as limiting the scope of the invention.